Flashing light after renovation traced to disturbed signal wire

What we found

When a fault starts after nearby work, the timeline matters. We checked connection points and the signal path before anything else.

• Flashing light started after nearby renovation work
• Fault onset aligned with the renovation timeline, not gradual wear
• Connection issue found in the signal wire path near the trunking

The signal path between indoor and outdoor sides was disturbed during the renovation. A wire connection in that path was no longer secure. This caused flashing errors and unstable cooling.

What we did

The boards are fine. The flashing error comes from the signal wire connection that was disturbed during renovation. Correcting and securing that connection restores communication between the indoor and outdoor sides. We retest cooling after to confirm everything is back to normal.

After the signal path was corrected and secured, the flashing light stopped and cooling returned to normal. No board replacement was needed.

What we learned

How to tell a board fault from a disturbed wire connection.

• PCB faults are usually gradual or related to age and power surges — a flashing error that starts the day after nearby renovation work almost always points to a disturbed connection, not a board failure.
• The signal wire between the indoor and outdoor units runs through the trunking. Work nearby can loosen or partially disconnect that wire, causing communication errors and flashing lights.
• Checking recent work areas and the signal-wire connection points first is much faster and cheaper than replacing a board — and in post-renovation cases, it almost always finds the cause.